To study the change in diet as human populations changed lifestyles from hunter-gatherers to agriculturalists, scientists measured carbon isotopes in the collagen tissues of human skeletons from North America.

Grady and colleagues compared dinosaur fossil evidence with evidence from living animal species to shed more light on the type of thermoregulation that dinosaurs used—ectothermy, endothermy, or mesothermy.

A team of scientists built a pedigree of a large extended family in Antioquia, Colombia, that has a high prevalence of early-onset familial Alzheimer’s disease due to a mutation in the PSEN1 gene. Worksheets also available in Spanish.

Charles David Keeling began measuring atmospheric carbon dioxide (CO2) in 1958 at the Mauna Loa observatory on the big island of Hawaii. This graph shows atmospheric carbon dioxide concentration in parts per million (ppm) by volume from 1958 to 2016. Worksheet also available in Spanish.